This invention relates to tubes or cannulae used for intubation within a body pathway, such as endotracheal, endobronchial, and tracheostomy tubes, and more particularly to such an apparatus having provision for removal of secretions that accumulate between the tube and the inner wall of the body pathway.
Representative of existing intubation apparatus are the endotracheal tubes of Chester, U.S. Pat. No. 4,305,392 and Goldin et al., U.S. Pat. No. 4,327,721. The typical use of endotracheal tubes is to promote a patient's respiration by providing for mechanical ventilation of a patient's lungs. Endotracheal tubes are usually cylindrical tubes which, when intubed, have a distal end residing within the trachea; the proximal end extending through the patient's mouth. A circumferentially extending inflatable cuff is positioned near the distal end of the tube and is inflated after intubation by way of an inflation lumen formed within the wall of the tube. The inflated cuff provides a seal between the tube and the tracheal walls which thereby allows oxygen or other gases to be forced into the lungs without escape through the mouth or nose of the patient.
Commonly, mucous secretions and other fluids accumulate along the intubated pathway above the inflated cuff. The amount of accumulations increases with the amount of time the endotracheal tube is in place. The patient may try to swallow the secretions, causing muscle contractions and tissue movement around the endotracheal tube, thereby contributing to the discomfort that is present during intubation. When the cuff is deflated accidentally or intentionally, such as prior to extubation, these accumulated secretions can enter the lower trachea and bronchi causing severe coughing and increasing the chance that the patient will contract pneumonia. Thus, a prime consideration in the use of any endotracheal tube is the efficient removal of accumulated secretions during intubation and especially just prior to extubation.
One method of removing these accumulated secretions is by inserting a suction catheter outside of and along the endotracheal tube between the tube and the wall of the intubated pathway. Such a procedure, however, results in irritation of the mucosa, stimulating the gag reflex of the patient. Furthermore, control of the suction catheter is difficult and thus it may be hard to avoid unintentional insertion of the suction catheter into the esophagus. As an attempt to remove secretions, the Chester patent shows the use of a suction chamber extending circumferentially around the endotracheal tube just above the cuff. Four ports are located about the periphery of the chamber, providing communication between the chamber and the area between the endotracheal tube and the tracheal wall. A lumen for suction of fluids extends from the suction chamber through the tube wall and out of the patient where it is connected with a suction source.
The positioning of the ports in Chester provides for removal of secretions directly above the cuff. However, secretions in a recumbent patient accumulate all along the endotracheal tube length above the cuff. Therefore, drainage ports located solely near the cuff would be inadequate to remove all of these accumulations. Furthermore, Chester and other prior art do not resolve the problem of occlusion of the suction lumen when blood clots, mucous plugs, or other obstructing material prevent removal of accumulations.